code: def setUp(self) -> None:
      self.search_space = SearchSpace(
          parameters=[
              RangeParameter(
                  "a",
                  lower=1.0,
                  upper=5.0,
                  parameter_type=ParameterType.FLOAT,
              ),
              RangeParameter(
                  "b",
                  lower=1.0,
                  upper=5.0,
                  digits=2,
                  parameter_type=ParameterType.FLOAT,
              ),
              ChoiceParameter(
                  "c",
                  parameter_type=ParameterType.STRING,
                  values=["a", "b", "c"],
              ),
              FixedParameter(
                  name="d", parameter_type=ParameterType.INT, value=2
              ),
          ],
          parameter_constraints=[],
      )
      self.t = Cast(search_space=self.search_space, observations=[])
      self.hss = get_hierarchical_search_space()
      self.t_hss = Cast(search_space=self.hss, observations=[])
      self.obs_feats_hss = ObservationFeatures(
          parameters={
              "model": "Linear",
              "learning_rate": 0.01,
              "l2_reg_weight": 0.0001,
              "num_boost_rounds": 12,
          },
          trial_index=9,
          metadata=None,
      )
      self.obs_feats_hss_2 = ObservationFeatures(
          parameters={
              "model": "XGBoost",
              "learning_rate": 0.01,
              "l2_reg_weight": 0.0001,
              "num_boost_rounds": 12,
          },
          trial_index=10,
          metadata=None,
      )
  
file_path: Ax/ax/modelbridge/transforms/tests/test_cast_transform.py
imports: from copy import deepcopy
  from unittest.mock import patch
  from ax.core.observation import ObservationFeatures
  from ax.core.parameter import ChoiceParameter, FixedParameter, ParameterType, RangeParameter
  from ax.core.search_space import HierarchicalSearchSpace, SearchSpace
  from ax.modelbridge.transforms.cast import Cast
  from ax.utils.common.constants import Keys
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_hierarchical_search_space
label_desc: Use image node_id 1 for calling the CastTransformTest obj's underlying member method code with example usage: obj.setUp() without return types